| (PET) is widely-used in many fields especially in apparel industry because it possesses a series of excellent physical and chemical properties such as high breaking strength and modulus, good resistance to acid, alkali, oxidant and bleaching solution and so on. On the other hand, there are many disadvantages such as poor hygroscopicity, poor warmth property and hard feeling of Polyethylene terephthalate (PET). Currently China has became world’s largest country for production and consumption of PET.Cotton fiber is an important textile material which possesses many excellent properties such as good hygroscopicity, softness and warmth. But in recent years, with China’s and the world’s population growing fast, grain is in critically short supply. To make sure that there is enough land to be used for farming, the government has taken a measure to reduce the land for planting cotton. According to the situation that supply of cotton is not adequate to the demand but PET’s supply is surplus and the situation that consumers asked for that clothing must be comfortable, convenient, safety and fashionable, the idea that the polyester would be modified by specific technology and the modified fiber would possess not only the excellent properties of PET but also the appearancecomfort and some other excellent properties of cotton came to people’s mind.This thesis synthesized three series of different multi-component polyester choosing the proper reaction conditions with the third monomer SIPE, the fourth monomer A which is polyol oligomer and the fifth monomer B which is polyol micromolecule. The structure and properties of the synthesized samples were characterized via NMR spectroscopy, Fourier transform infra-red spectroscopy (FT-IR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetry analysis (TGA). Two copolyester samples whose comprehensive properties are relatively better than other samples were selected to be spun as fiber and the properties of the fiber such as mechanical property, orientation, crystalline, moisture regain and warmth property were characterized,the results were as follows:1.The result of FT-IR showed that there were several major feature peaks showed on the spectrogram. The proportion of the third monomer SIPE, the fourth monomer A and the fifth monomer B in polymer is almost the same with the proportion of SIPE, A and B by NMR spectroscopy.2.The result of DSC showed that the glass transition temperature (Tg), the cold crystallization temperature(Tcc) and the melting point Tm of the first series samples all reduced with the increase of A content; the Tg and the Tcc of the second series samples both reduced but the Tm rose with the increase of B content; the Tg of the third series samples reduced with the increase of B content, but the Tcc and the Tm both disappeared.3.The result of TGA showed that with the third monomer SIPE, the fourth monomer A and the fifth monomer B, the apparent activation energy reduced which showed the comonomers had effect on the thermal stability of copolyester.4.The result of intrinsic viscosity of samples that were heated by different temperature and time showed that the third series samples’thermostability is best among the three series samples.5.The tensile strength, initial modulus, orientation and crystalline of the fiber were decreased and the elongation rose with the increase of B content while the A content kept constant. With the flexible A and B introduced, the crystallinity of polyester fiber reduced and the grain increased, which increased the flexibility of the amorphous molecules. This structure would help to improve the flexibility of fiber; Because of A and B, the moisture regain and the warmth index Qmax of the modified fiber were higher than PET fiber and with the increase of B content, the moisture regain and the warmth index Qmax were boost with a narrow range. |
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